//封装倒计时
import dayjs from 'dayjs'
import { onUnmounted, ref,computed } from 'vue'
export const useCountDown = () => {
  let timer = null
  const time = ref(0)
  const formatTime = computed(()=> dayjs.unix(time.value).format('mm分nn秒'))
  const start = (currentTime) => {
    time.value = currentTime
    timer = setInterval(()=>{
      time.value--
    },1000)
  }
  //组件销毁，清除定时器
  onUnmounted(()=> {
    timer && clearInterval(timer)
  })
  return {
    formatTime,
    start
  }
}
